In the routine assessment of periodontal tissue suspected of disease a probe consisting of a rod with a round end is pressed into the gum pocket until a sense of resistance is felt, at which point the depth is estimated relative to the rod. In some subjects bleeding occurs readily, indicating less than normal strength of the walls of the capillary vessels and other tissues. However, the force necessary to induce bleeding is subjectively sensed, not measured relative to an objective quantum of force or weight. In subsequent assessments, after treatment, the degree of improvement can be determined only to the extent that the improvement is of a significance greater than the inherent subjectivity of the sense of force applied by the dentist. Thus the efficacy of the treatment has not heretofore been subject to objective measurement.